University of Pretoria (1990)

Studies on performance and efficiency of pure and crossbred cattle in an arid bushveld environment

Van Zyl Jacobus Gerhardus Eduard

Titre : Studies on performance and efficiency of pure and crossbred cattle in an arid bushveld environment

Auteur : Van Zyl Jacobus Gerhardus Eduard

Université de soutenance : University of Pretoria

Grade : Doctor of Philosophy (Ph.D.) 1990.

Résumé The influence of pure (Afrikaner, Hereford, Bonsmara and Simmentaler) and crossbred (various combinations of Afrikaner with Simmentaler and Hereford) cattle, as well as some genetic and nongenetic factors (sex of calf, year and season of birth, productive status and age of dam) and first-order interactions on parameters of economic importance were investigated. These parameters were birth mass, weaning mass, calving interval (CI) and cow productivity ((365 $\div$ CI) x weaning mass). Data was collected at Mara Research Station in the Northern Transvaal from 1972 to 1984. Amongst pure-bred cattle, Simmentaler calves were heavier (P $